Method of making thread, and resulting article



Sept. 3, 1940.

METHOD OF MAKING THREAD, AND RESULTING ARTICLE Filed Jan. '22, 1938 5 BAND UNDER TENSION MA\NTA|N STRETCH AND APPLY HEAT CONTRACT AND COOL INCREASE D STRETCH INVENTOR erharol Vinck TTORNEY G. VINCKE 2,213,659

Patented Sept. 3, 1940 UNITED STATES PATENT DFFE QE METHOD OF MAKING THREAD, AND RESULTING ARTICLE Application January 22, 1938, Serial No. 186,319

4 Claims.

My present invention relates to thread, as thread for use in weaving, particularly to thread made from rubber or rubber-like material, and more particularly to a thread of this type which is resistant to chafing.

My present method and the article resulting from the practicing of such method is particularly directed to the production of a thread made from rubber or rubber-like material and having a relatively high resistance to fraying as a result of chafing. A serious objection to rubber thread or thread from rubber or rubberlike material, when used in weaving is the relative ease with which such thread frays as a result of being intermittently or continuously chafed by engagement with moving parts of a loom. Under the conditions of weaving and with certain types of thread the fraying is particularly ragged with the result that there is a serious breakage of thread during the weaving operation.

Rubber or rubber-like thread when used in weaving operations is invariably held under more or less tension and thread of this character is more easily frayed than other kinds of thread. It has been suggested to reduce the tendency to fray because of chafing to alter the characteristics of the material, as for example, adding to the rubber substances to be utilized as fillers and as softeners with the idea of producing a thread which will be more resistant to the chafing action. It has also been suggested that the tension in the thread as it is being woven should be reduced, but the resulting woven fabric is unsatisfactory and it has been found impossible to produce a satisfactory fabric unless the various threads employed are woven under tension. Therefore the suggestions heretofore advanced have had to be discarded. Under some circumstances the only remedy at present known to reduce the fraying due to chafing and therefore the resultant breakage of the thread is to encase the thread in a layer of vegetable or animal fiber, such as rayon, cotton, or silk.

Particularly rubber thread produced directly from liquid latex has a pronounced tendency to fray.

It has long been the practice to manufacture rubber thread from Para rubber which is the type that even today best withstands chafing, but with Para rubber one cannot obtain such nice light colored threads, as with latex or crepe rubber, and the modern trend of the trade demands such light shades.

The present invention refers specially to a latex thread which has the desirable feature of withstanding rubbing or chaffing to a far greater extent than heretofore.

Taking advantage of the known fact that the less tension in a thread of rubber or rubberlike material the greater the ability of such' thread to withstand chafing, I have devised the method of the present invention and by practicing such method I am able to produce a thread in which the breakage of the thread due to fraying caused by the chafing of the thread against moving parts of the loom is obviated.

An object of my invention therefore, is an improved method of making thread from rubber or rubber-like material.

An object of my invention is an improved thread made from rubber or rubber-like material.

In the accompanying drawing,

Fig. 1 is an elevation, partly in section, of a length of composite thread made according to the present invention;

Fig. 2 is a sectional end elevation taken on the line 2--2 of Fig. 1,,and

Fig. 3 is a diagrammatic lay-out or flowsheet, illustrating a mechanism by which my improved method may be practiced.

Referring to the drawing, and particularly to Figures 1 and 2, I0. designates a rubber thread, or a thread made from resilient material, surrounded by a cover H formed also of rubber or rubber-like material. The thread It may be made from a band of rubber or rubber-like material wound upon itself into a compact cylindrical mass in cross-section as shown in Figure 2. Also the covering M is made from a band of rubber or rubber-like material wound upon the thread It. The bands from which the elements H) and H are made may have the same characteristics or different characteristics and may be Wound under the same conditions or under different conditions. With regard to the present invention however, it is preferable that the thread it? formed from a band of rubber or rubber-like material be wound under tension and that after being so wound the resultant thread is stretched and while in such stretched condition is subjected to heat, after which the thread is allowed to cool and therefore contract in length. Afterwards the cool thread is again stretched to any desired degree, after which the wrapping H is placed thereon and preferably without tension. The resultant composite thread is then vulcanized and is ready for use.

Referring to Fig. 3 wherein is shown diagrammatically apparatus by means of which various above defined operations may take place, l2 designates a band or film of rubber or rubberlike material formed in any suitable manner and passed over, thence under and away from a roll l3 under tension, the result being a closely rolled band or film wound in helical form upon itself and resulting in the thread l0. From the roll l3, the thread 10 is drawn by the roll I4, and due to the difference in peripheral speed of the roll M as compared with the roll l3, the thread is stretched to any desired degree. From the roll M the thread ll] is drawn by a roll 15 through a heating device 16 which applies heat and maintains the stretch in such thread l0 placed in the same by the stretching process produced by the roll M. The heat thus applied removes the internal stresses set up in the thread l0 during the making and stretching thereof.

From the roll IS the thread l0 passes along over a roll I! having peripheral speed less than the peripheral speed of the roll IS. The thread in being then in the open air or, if desired, under the influence of any cooling medium, cools and contracts in length. From the roll ll the thread passes over, thence under, and again over a roll l8 which has a peripheral speed greater than the peripheral speed of the roll I! and therefore the thread i0 is again subjected to a stretching operation. Passing over the roll IS in such a manner as to enclose the thread I0 is a band or film H! of rubber or rubber-like material which in the rotation of the roll l8 rolls the band or film IS on the thread [8 resulting in the covering ll being ,placed on the thread I0. From the roll l8 the composite thread composed of the core [0 and the outer covering I l passes through a vulcanized apparatus 20 ready for use.

In carrying out my invention, and particularly my improved method, I preferably form the thread from two or more films or bands of rubber or rubber-like material, each film or band being of a material having the same characteristics, or each film or band having different characteristics, and roll such films or bands into a thread by rolling the films upon each other in .helical form and under no or any desired tension. There is thus produced a composite thread in which there is a core or central portion overlaid with an outer or covering portion, and in which the core portion is preferably wound under greater tension than the covering portion and in which the covering portion may be wound on the core portion with preferably little or no tension.

In one form of my invention I preferably utilize the core portion made from a film or band of rubber or rubber-like material, such for example, as a film or band of latex or a natural or artificial dispersion of rubber, and wound in helical form upon itself either without tension or under tension and the resulting thread is then preferably heated to destroy the internal stresses set up in the material during the forming and winding operation, after which the thread is allowed to cool.

One form of my invention, therefore, is that improved method of making rubber threads from bands of rubber in which the first band is rolled upon itself while holding the band under tension, then partly vulcanizing the thread by subjecting the same to heat, stretching it to the desired degree, then surrounding the thread with a band of rubber having little or no, tension, and vulcanizing the then completely formed thread at a predetermined length and by subjecting such formed thread to the action of heat.

After cooling the thread may be further stretched and again heated to remove the internal stresses set up, when it may be allowed to cool. The resulting thread may then be placed under any desired tension and overlaid with a film or band of rubber or rubber-like material wound either with the lay thereof lying in the same or in the opposite direction to the lay of the helical winding in the thread referred to. Such overlaid film or band may be laid without tension or little tension and there is therefore produced a composite thread in which the core portion is a thread under tension overlaid with a covering which is without tension or with little tension. Such composite thread therefore after the overlaying operation, will contract in length, and on the original amount of stretch or elongation in the core thread, will depend the degree of the compression which is exerted on the outer or covering portion of the composite thread. Such thread when used in weaving operations may be stretched, as is considered necessary in weaving such thread, and the amount of stretch to which the thread is subjected will be insuflicient to place such a stretch or tension in the outer layer or outer covering as would make the thread susceptible to chafing. The result: is that the thread used in the weaving operation, while as a whole is under tension, as required for the weaving operation, yet that portion thereof which comes into rubbing engagement with the working parts of the loom is practically inert and resists to the maximum degree the fraying effects due to chafing.

If desired, the stretched thread referred to above and constituting the inner or core portion of the composite thread may have the second or covering layer placed thereon in a helical direction and under any desired tension and such composite thread may again be overlaid with another outer covering which may be under little or no tension and thus a composite thread of more than two'layers may be produced and in which the outer or covering layer is in the best mechanical condition to withstand the fraying effects of chafing.

Such a thread has been found to have a considerably longer life than threads as heretofore made, as it is well known in this art that the aging qualities of a thread are improved whenthe material of the thread is quiescent or not under tension. It has been found that a tensioned rubber is chemically more susceptible to attack. Such as for example, oxidation, and light, than a thread the material of which is at rest.

Reference is hereby made to my copending application, Serial No. 186,275, filed January 22, 1938, which discloses a mechanism by means of which the above described methods may be successfully carried out.

Nevertheless I do not limit my invention of this new thread to be made from rolled thread alone as it is possible that a similar article may be produced parting from any rubber thread manufacturing method, stretching the produced thread and giving it an outer coating of rubber by a continuous dipping or extruding or spraying process, so that this outer layer is practically under compression when the tension of of the material, stretching the thread to a dethe core has been released.

Vulcanized latex such as is known in the trade by the name of Vultex or Revultex may be advantageously used for this process.

I claim: a

1. A method of making rubber thread from two bands of rubber or rubber-like material which consists in rolling the first band upon itself while under tension, heating the resultant thread in order to release the internal stresses sired degree, surrounding it with a rubber band having little or no tension, and vulcanizing the composite thread at a predetermined length.

2. A method of making rubber thread from two bands of rubber which consists in rolling the rst band upon itself while holding the band unden' tension, partly vulcanizing the thread, stretching it to a desired degree, surrounding the thread with a band having little or no tension, and vulcanizing the formed thread at a predetermined length.

3. That improved method of manufacturing a thread from rubber or rubber-like material which comprises winding a band of the material upon itself in a helical path, elongating the resulting thread, heating the thread while elongated to remove internal stresses developed during the winding and stretching, cooling the thread while allowing the same to contract in length, elongating the thread beyond the point to which it was first stretched, heating the same to. remove the internal stresses set up during the stretched operation, cooling the same and then overlaying the thread with a layer of rubber wound thereon in a helical path without tension.

4. That improved method of manufacturing a thread from rubber or rubber-like material which comprises winding a band of the material upon itself in a helical path, elongating the resulting thread, heating the thread while elongated to remove internal stresses developed during the winding and stretching, cooling the thread while allowing the same to contract in length, elongating the thread beyond the point to which it was first stretched, heating the-same to remove the internal stresses set up during the stretched operation, cooling the same, then overlaying the thread with a layer of rubber wound thereon in a helical path without tension, and then vulcanizing.

GERHARD VINCKE. 

